I hope the racers among us (not fast bus drivers, but real racers) will echo JPJ's comments and also reflect on how critical such things as balance, tire pressures, and the condition of braking systems are.

One problem our buses have that is not uncommon is a propensity to have leaking hub or axle seals. Left unnoticed for a while the leaking axle grease ends up on the brake linings or pads greatly reducing the effectiveness of that brake.

My point is that speed alone is not our only potential cause for problems. There are so many factors that affect our safety (to say nothing of the fact that the average car stops in 130 feet at 60 MPH and it takes us about 300) that we literally have to constantly adjust to our driving conditions.